import re
re.match(pattern, string, flags=0)
re.search(pattern, string, flags=0)
re.sub(pattern, repl, string, count=0, flags=0)

pattern = re.compile(pattern[, flags])
pattern.findall(string[,pos[,endpos]])

re.finditer(pattern, string, flags=0)
re.split(pattern, string[, maxsplit=0, flags=0])